Mortar and pestle



Z 14 m Wag Jul 30, 1940. E CH TT 2,209,386

MORTAR AND PESTLE Filed Nov. 3, 1938 [it We 72 for; Eda 24711:. 6%015,

Patented July 30, 1940 UNITED STATES PATENT OFFICE 2,209,386 MORTAR AND PESTLE :Edward L. 'Cliott, Chicago, 111. Application Novemberii, 1938, Serial No. 238,549

10 Claim.

This invention relates tomortarsand .pestles and more particularlyto devices-of this character for prepared dental amalgams and other characteristically similar mixtures.

As is well known, dental amalgams usually comprise a triturated mixture of a characteristic metal alloy and mercury. According to thecustomary practice and owing to the peculiar nature of the work in which it is used, only a relatively small quantity of the amalgam is prepared at any one time and in its preparation, accuracy in the proportioning of the respective ingredients, and thorough mixing and amalgamation thereof under selective predetermined pressures are essential in order to achieve proper results-and this pressure must not be exceeded or reduced when once adjusted.

The principal object of the present invention is to provide a mortar and pestle having distinct advantages over the devices shown and described in my copending application Serial No. 138,077, filed April 21, 1937, and in addition, provided with novel means for making certain that the trituration is accomplished at -a definite pressure such as 1, 2, 3,4, or pounds, these limits being the usual ones used and that the same shall not be exceeded at any position of the pestle with respect to the mortar. However, other pressuresmay be used if desired, as will be apparent from the following description, reference being had to the accompanying drawing wherein:

Fig. -1 is a side view of an embodiment of my invention showing the mortar partly in section;

Fig. 2 is an enlarged sectional elevation longitudinally of the device;

Fig. 3 is anelevation of the pestle-removed from the mortar;

Fig. 4 is a plan view of the mortar;

Fig. 5 is a view similar to Fig. 4 with the pestle mounting omitted;

Fig. -6 is a side elevation of the mortar as shown in Fig. 5;

Fig. 7 is a fragmentary plan view of the pestle mounting; and

Fig. 8 is a fragmentary sectional view taken on the line 88 of Fig. 4.

Referring more particularly to the drawing, I ll designates the mortar of glass or other vitreous material, although the same may be of plastic or other composition, a condensationproduct such as Bakelite material or otherwise. :It maybe stated, however, that frosted glass is preferred as it gives the best grinding surface. -'l l designates the pestle which, generally speaking, is :of metal. The mortar has a cylindricalbore l2 and a flat base or bottom and is open at the top while an annular concaved portion l 3 projectingoutwardly of the bore or wall [2 and of the same arc or curvature as ball 31 is provided at the juncture of the side and bottom in which it-he pulverizing inclined ribs l5 spaced apart to cooperate with 5 the bearing portion of the .mortar designed to support the pestle for gyratory motion in pulverizing the material. This bearing portion is shown as comprising a band it preferably of metal having a plurality of lugs ll, shown as 4 10 in number and pressed in from the wall of "the band at the bottom edge of the latter so as to engage at the slots between the ends of the ribs or threads [5 and eifectively secure the band .in

position on the mortar but to permit convenient and quick removal or replacement thereof.

The band vi 6 is provided with a spider including a plurality, preferably 3, right-angled spokes, arms, or legs l8 havingv vertical portions, the

lower extremities of which may be formed with the band, soldered, spot-welded or otherwise joined thereto and horizontal portions branching from a central plate or bearing portionlg having .a circular openingZll forming a seat which is provided with an outwardly flared or upwardly beveled edge 2|.

The pestle comprises an operating member, gripping portion or handle including a cylindrical outer tube or sleeve '22 having a bore .23 .openat the top and an internally threaded bottom ,por-

tion 24. A semi-spherical enlargement or bearing member 25 engages the seat 29 for universal movement and hasa reduced externally threaded neck portion 26 of tubular form projecting upwardly therefrom radially and axially for adjustable connection with the threads 2 of tube .22 to adjust the spring tension as well as to insure proper seatingengagement of the mernber25 with the seat 20. This spherical member may have its lower .face flat but is bored out radially and :axially through the tubular neck portion Zliand may be provided with a suitable diametrical groove '21 for reception of a screw driver in attaching the same to the .tube 22. The .bore of the spherical neck portion is smooth and snugly .45

and slidably continuous and receives the lower end of a cylindrical rod '28, the upper :end .of which terminates adjacent the upper end of the tube "22, the said rod being loosely received in or spaced from the inner wall of the tube 22 and 1 having a bore 29 in its lower portion. The tube 2 2 is provided at diametrically opposite points with circular openings 30, andthe tubular portion of the rod '28 is provided with diametrically opposite apertures 3| registering with the openings 1'55 30. A cylindrical plug 32 is inserted in the bore 129 of the rod 28 against the upper end thereof and has a diametrical openingfit registering with ltheapertures 31 to take a cross pin 34 the ends of which extend into the openings .130 for limited movement therein serving to permit limited movement of the rod 28 within the tube 22 but prevent displacement thereof, for a purpose to be hereafter made apparent. The lower section of the pestle which includes a handle or operating member, has a bendable or spring steel section or shank 35 which is carried by or formed with the plug 32 and constitutes the lower section of the I pestle. This shank or section is loose in the bore 29, that is, entirely spaced from the wall thereof and the opening in the spherical portion 25 from which it depends or projects downwardly and is provided with an externally screw threaded enlargement 36 welded, soldered, formed with or otherwise secured to the lower end of the shank to mount a crusher ball 31 of the same are or curvature as the concaved annular portion l3 and adapted to lit the same as seen in Figs. 1 and 2. The crusher ball has a tubular shank or sleeve portion 38 which is internally threaded to engage the enlargement 36 for adjustment so that proper pressure will be exerted upon the material and is locked in position by a lock nut 39 threaded on the enlargement against the upper end of the sleeve portion 38. By this means, two adjustments of the pressure are provided in connection with the adjustment later described.

A short bearing sleeve 40 is disposed on and snugly fits the rod 28 within the bore of the sleeve 22 and has a pair of diametrically opposite longitudinal slots 4| in its lower end fitting over the pin 34 so as to snugly fit the sleeve and guide the rod in its movements as well as to prevent the parts from being loose or rattling. A compression spring 42 is fitted in the bore of the sleeve 22 around the rod 28 and against the upper end of the bearing sleeve 40 while the top thereof projects from the upper end of the sleeve. A cap 43 telescopes over the sleeve and upper end of the spring and has a thickened portion 44 at the bottom provided with a threaded radial aperture 45 receiving a set screw 46 having a knurled head 41, the set screw being designed to engage the sleeve externally to hold the cap in adjusted position according to the pressure desired. against the material being pulverized or triturated. This adjustment with that at the crusher ball provides a dual means of adjustment. The cap 43 is provided with a counter bore 48 at the bottom forming an end wall 49 which provides a seat for the compression spring 42 and a cross bar 50 extends through a diametrical opening in the solid upper end of the cap to facilitate turning of the pestle. Calibrations or gauge lines are provided on the outer surface of the sleeve and may be suitably marked with indicia of standard pressure such as 1, 2, 3 and 4 representing pressure in pounds exerted by the pestle in the mortar as will more fully appear hereinafter. These calibrations cooperate with an indicator formed by the bottom edge 52 of the cap at which the pressure is read on the scale. A space 53 is normally provided between the sleeve and the beveled edge of the bearing or seat at the circular opening 20 in the top or supporting portion of the mortar and normally the pestle is disposed at an inclined angular position with respect to the mortar and adapted by the adjustment of the telescopic sections of the pestle due to the action of the compression spring to cause the crusher ball to exert a certain definite pressure against the material in the mortar. This pressure cannot be increased by moving the pestle laterally outwardly as indicated in dotted lines in Fig. 2 owing to the fact that the shank 35 is adapted to bend as far as the inner wall of the tubular lower portion of the rod 28 and will be limited in its movement thereby and by engagement of the parts 24 and 25 with the wall 2| of the opening 20 in the plate or bearing portion l9, but will prevent pressure in excess of the adjusted pressure from being exerted outwardly against the material at the vertical or lateral wall of the mortar chamber.

Thus, when the pressure of the spring 42 is set at a definite point, such as four pounds, and. the pestle with its crusher ball is gyrated or revolved in its normally inclined position, it being understood that in practice no particular downward pressure is exerted thereon at the handle or crossbar 5!], this pressure will remain constant and may be predetermined by adjustment as described. Since the lateral angular movement of the upper portion or handle of the pestle and thus the out- Ward pressure of the ball against the lateral wall of the mortar chamber is limited by engagement of the base of the handle portion with the edge of the opening 20, the bending of the resilient shank or section 35 is thereby limited as shown in dotted lines and Figs. 1 and 2 of the drawing, so that the pressure will not be increased and the outward pressure of the ball against the mortar will be well below the downward pressure. For example, when the downward pressure is four pounds the outward pressure is usually about two pounds as the bending action will remain within the elastic limit of the material of which the resilient section or shank is made. Since the outward movement of the pestle is arrested, as above described before engagement of the resilient shank 35 with the peripheral lower edge of the bore 29, this lateral pressure of the ball is therefore limited, and excessive pressure against the material being triturated thereby avoided. The usual central upward projection of concaved, con- Vex, or conical form, forming a bump at the center of the base or bottom of the mortar in the principal triturating or mixing chamber, is also omitted, so that excessive pressure cannot be exerted by moving the pestle to a vertical position but the latter may be freely rotated or moved in a circular orbit at an inclined angle when in use, in which position the spherical part and its seat will form a bearing allowing the necessary universal movement while the spring will allow the necessary longitudinal movement of the crusher ball and parts to which it is connected including the rod, to compensate for the material within the mixing chamber of the mortar. This movement will also be allowed by reason of the cross pin 34 moving in the openings 30 of the sleeve although normally if the pestle is disengaged from the mortar, the pin will be held in the downward position in-said openings, as shown in Fig. 3 by the spring 42.

From the foregoing, it is thought that the operation of the device will be apparent, but it may be mentioned that during the rotation of the pestle in an inclined position, the resilient bendable shank or section thereof notably located at its lower end and below the universal bearing,

will serve as a compensating connection between the pestle and the mortar and particularly between the crusher head or ball and the pestle proper and more especially the universal bearing thereof, whereby undue strain on the parts or excess pressure above a set pressure against the material being pulverized will be absolutely prevented.

Another advantage of the construction is that the mortar is open at the top'so that the material being triturated is at all times visible whereby the condition thereof may be ascertained and the operation discontinued at the proper time.

While I have illustrated and described the preferred form of construction for carrying my invention into effect, this is capable of variation and modification without departing from the spirit of the invention. I, therefore, do not wish to be limited to the precise details of construction set forth, but desire to avail myself of such variations and modifications as come within the scope of the appended claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A pestle comprising interfitting telescoping tubular sections, means to hold said sections in adjustable relation, and a crusher ball resiliently supported from said sections and adapting the ball for limited longitudinal movement, and

lateral movement in angular relation to the longitudinal axis of said sections and means to limit said outward movement.

2. In a mortar and pestle, a mortar having a .mixing chamber, a bearing member removably mounted thereon and having a circular'opening, a pestle having a semi-spherical portion engaged at the opening for universal movement and a crusher ball, said pestle comprising telescoping tubular members entirely above the. bearing member, means for exerting pressure against one of said members, said crusher ball having a resilient shank connected to the latter tubular member within and above the lower end thereof for limited lateral movement limited by contact with the insides of the tubular member.

3. In a mortar and pestle, a pestle comprising a handle, a crusher ball, a resilient connection between said handle and ball permitting limited lateral movement of the ball relative to the longitudinal axis of the handle, and means carried by the mortar forming a bearing for said han dle and limiting the lateral angular movement of the handle before the limit of lateral movement of the ball with relation to the axis of said handle is reached.

4. In a mortar mixing chamber, a bearing member removably mounted. thereon and having a circular opening, a pestle comprising an operating handle, a semispherical bearing on the lower end thereof and engaged in the opening for universal movement, a crusher ball having a resilient shank connected to said handle within and above the lower end thereof, means providing. a predetermined downward pressure between the ball and mortar, said opening in the bearing being proportioned to engage said handle above said semi-spherical bearing and limit the lateral movement thereof before the lateral pressure of the ball against the side of the mortar exceeds the predetermined downward pressure thereof.

5. In a mortar and pestle, a mortar having a mixing chamber, a bearing member removably mounted thereon and having a circular opening, a pestle comprising an operating handle, a semispherical bearing on the lower end thereof and engaging in the opening for universal movement, the lower end of said handle having a longitudinal bore, a crusher ball having a resilient shank extending into said bore and anchored remote and pestle, a mortar having a from the lower end thereof, means providing a predetermined downward pressure between the ball and mortar, said opening in the bearing member being proportional to engage said handle above said semi-spherical bearing and limit the lateral movement thereof before the resilient shank of the crusher ball engages the pe-,

I ripheral edge of the end of the bore.

6. In a mortar and pestle, a pestle comprising telescopic sections,'means for holding said sections in adjustable relation, a crusher ball having a resilient shank longitudinally movable within the telescopic sections, and having a limited lateral movement relative to the axis of the handle means limiting the outward movement thereof, resilient means interposed between one of said telescopic sections and said shank producing a predetermined downward pressure between the ball and mortar and a universal bearing connecting said mortar and pestle and limiting the lateral angular movement of the pestle.

7. In a mortar and pestle, a pestle comprising telescopic sections, means for holding said sections in adjustable relation, a crusher ball hav ing a resilient shank longitudinally movable within the said telescopic sections, said shank permitting lateral movement of the ball with relation to the axis of the handle, means limiting the outward longitudinal movement thereof,

resilient means interposed between one of said telescopic sections and said shank, a universal connection between said mortar and pestle, said universal connection limiting the lateral angular throw of the pestle before. the limit of said lateral movement ofthe ball is reached.

8. In a mortar and pestle, a mortar having a mixing chamber, a bearing member removably mounted thereon and having a circular opening, a pestle comprising upper and lower telescopic handle sections, means to hold said sections in adjusted relation, a semi-spherical bearing portion at the lower end of one of said sections and engaging the said opening for universal movement, a rod longitudinally movable in said lower section, a crusher ball, resilient means connecting said ball and said rod, means yieldingly pressing said rod and crusher ball downwardly and means limiting the longitudinal movement of said rod and ball.

9. In a -mortar and pestle, a mortar having a mixing chamber, a bearing member removably mounted thereon and having a circular opening,

a pestle comprising upper and lower telescopic handle sections, means to hold said sections in adjusted relation, a semi-spherical bearing mem-- her on the lower section and engaging in the opening for universal movement, a rod longitudinally movable in said lower section, means limiting the longitudinal movement thereof, the

lower end of said rod having a longitudinal bore, a plug fitting snugly in said bore remote from the outer end thereof, a crusher ball, and a re- EDWARD L. CHOT'I'. 

